Ester-alcohol solvent

Texanol Ester-Alcohol solvent, architectural aq. coalings... 

Rhodiasolv RPDE solvent, PVAc Dllsobutylphthalate NMP solvent, PVAc latex Texanol Ester-Alcohol solvent, PVAc-acryllc latex Texanol Ester-Alcohol solvent, PVB Diisobutyl phthalate solvent, PVB resins 3-Methoxybutanol solvent, PVC Dllsobutyl phthalate solvent, PVDF NMP... 

Donoi—acceptoi chromogens in solution are often strongly affected by the nature of the solvent or the resinous substrate in which they are dissolved. The more polar the solvent or resin, the longer the wavelength of the fluorescent light emitted. Progressing from less polar to more polar solvents, the bathochromic, or reddening, effect of the solvents on the dye increases in the order of aUphatics < aromatics < esters < alcohols < amides. 

The principal component of primary amyl alcohol, 1-pentanol, although itself a good solvent, is useful for the preparation of specific chemicals such as pharmaceuticals and other synthetics (153,154). Production of primary amyl acetate and its esters for solvent appHcations has seen low growth since the 1970s because of the decline of nitroceUulose lacquers and the introduction of new solvent systems. 

In terms of general solvency, solvents may be described as active solvents, latent solvents, or diluents. This differentiation is particularly popular in coatings applications, but the designations are useful for almost any solvent appHcation. Active solvents are strong solvents for the particular solute in the apphcation, and are most commonly ketones or esters. Latent solvents function as active solvents in the presence of a strong active solvent. Alcohols exhibit this effect in nitrocellulose and acryUc resin solutions. Diluents, most often hydrocarbons, are nonsolvents for the solute in the apphcation. 

The equihbrium shown in equation 3 normally ties far to the left. Usually the water formed is removed by azeotropic distillation with excess alcohol or a suitable azeotroping solvent such as benzene, toluene, or various petroleum distillate fractions. The procedure used depends on the specific ester desired. Preparation of methyl borate and ethyl borate is compHcated by the formation of low boiling azeotropes (Table 1) which are the lowest boiling constituents in these systems. Consequently, the ester—alcohol azeotrope must be prepared and then separated in another step. Some of the methods that have been used to separate methyl borate from the azeotrope are extraction with sulfuric acid and distillation of the enriched phase (18), treatment with calcium chloride or lithium chloride (19,20), washing with a hydrocarbon and distillation (21), fractional distillation at 709 kPa (7 atmospheres) (22), and addition of a third component that will form a low boiling methanol azeotrope (23). 

Aldehydes can be dkeedy converted to esters using bromine in alcohol solvents with sodium bicarbonate buffer (41). 

Higher butyryl esters, formulated with acryUc polymers, provide coatings with excellent weather resistance, good colorfastness and dispersibiUty, and good flow properties (154). Formulations for a typical automotive refinishing lacquer and a wood furniture lacquer are given in Tables 12 and 13, respectively. Low viscosity, high butyryl cellulose esters tolerate substantial amounts of alcohol solvent without appreciable increase in solution viscosity. 

Solid esters are easily crystallisable materials. It is important to note that esters of alcohols must be recrystallised either from non-hydroxylic solvents (e.g. toluene) or from the alcohol from which the ester is derived. Thus methyl esters should be crystallised from methanol or methanol/toluene, but not from ethanol, n-butanol or other alcohols, in order to avoid alcohol exchange and contamination of the ester with a second ester. Useful solvents for crystallisation are the corresponding alcohols or aqueous alcohols, toluene, toluene/petroleum ether, and chloroform (ethanol-free)/toluene. Esters of carboxylic acid derived from phenols... 

After washing the ether-benzene layer, the solvents are eliminated in vacuo and an ester-alcohol is thus obtained with a yield of 98%, in the form of a transparent resin. This resin, if treated with petroleum ether, yields 6.35 g of ester-alcohol in the form of fine needles (MP = 66.68°C) which are very soluble in the chief organic solvents and in petroleum ether. 

Cellulose nitrate Air drying Solvent evaporation Blends of esters, alcohols and aromatic hydrocarbons Fairly good Bad Good Poor Very good Fire hazard Statutory regulations governing use... 

Interestingly, certain chiral tertiary bases, viz., the Cinchona alkaloids, result in an asymmetric 1,3-elimination to give enantiomerically enriched azirine esters 29 (Scheme 15). The best results were obtained with quinidine in toluene as the solvent at a rather high dilution (2 mg mL ) at 0 °C. In an alcoholic solvent no asymmetric conversion was observed. It is of importance to note that the pseudoenantiomers of the alkaloid bases gave opposite antipodes of the azirine ester, whereby quinidine leads to the predominant formation of the (k)-enan-tiomer (ee = -80%). To explain this asymmetric Neber reaction, it is suggested... 

Another important argument for the use of the organic solvent is the reverse hydrolytic reactions that become feasible [61,75]. The inhibition of the biocatalyst can be reduced, since the substrate is initially concentrated in the organic phase and inhibitory products can be removed from the aqueous phase. This transfer can shift the apparent reaction equilibrium [28,62] and facilitates the product recovery from the organic phase [20,29,33]. A wide range of organic solvents can be used in bioreactors, such as alkanes, alkenes, esters, alcohols, ethers, perfluorocarbons, etc. (Table 1). 

The reaction of aldehydes with MnOz in the presence of cyanide ion in an alcoholic solvent is a convenient method of converting aldehydes directly to esters.214 This reaction involves the cyanohydrin as an intermediate. The initial oxidation product is an acyl cyanide, which is solvolyzed under these reaction conditions. 

Parathion is very slightly soluble in water (20 parts per million), but is completely miscible in many organic solvents including esters, alcohols, ketones, ethers, aromatic and alkylated aromatic hydrocarbons, and animal and vegetable oils. It is practically insoluble in such paraffinic hydrocarbons as petroleum ether, kerosene, and refined spray oils (about 2%) unless a mutual solvent is used (1). 

Allyl pyridinium betaines 441 isoelectronic with enol betaines 427 likewise reacted with diphenyl cyclopropenone by elimination of pyridine272,213 The product formation, different in aprotic and protic media (phenol 443 in aprotic solvent, A3,5-hexadienoic esters 445 in alcohol solvent), suggested that the diene... 

The efficiency of the extraction depends on the coordinating ability of the solvent, and on the acidity of the aqueous solution which determines the concentration of the metal complex. Coordinating ability follows the sequence ketones > esters > alcohols > ethers. Many metals can be extracted as fluoride, chloride, bromide, iodide or thiocyanate complexes. Table 4.5 shows how the extraction of some metals as their chloro complexes into diethyl ether varies with acid concentration. By controlling... 

Typically, solvents are screened to identify one that gives optimal results. Assuming that the substrate and catalyst are soluble, solvent polarities varying from alkanes, aromatics, halogenated, ethers, acetonitrile, esters, alcohols, dipolar aprotic to water have been used. An example of this, using a ketone and the rhodium cp TsDPEN catalyst, is shown in Table 35.3. Further optimization of this reaction improved the enantiomeric excess to 98%. A second example involved the reduction of 4-fluoroacetophenone in this case the enantioselectivity was largely unaffected but the rate of reduction changed markedly with solvent. Development of this process improved the optical purity to 98.5% e.e. 

It was Ayusman Sen [8] who discovered in 1982 that the use of weakly coordinating anions and phosphines as the ligands together with palladium yielded much more stable and active catalysts for the formation of polyketone from CO and ethene in alcoholic solvents. Cationic palladium-(triphenylphosphine)2(BF4)2 gave a mixture of oligomers having methoxy ester... 

Possible slight effects from carboxylic acids, anhydrides, aromatic and aliphatic hydrocarbons, alcohols, aldehydes, ketones, esters, chlorinated solvents... 

As the supported glycol catalysts worked better in promoting reactions in a single solvent system, we explored the direct carbonylation of benzyl halides using an alcohol solvent, base, and cobalt carbonyl. Our initial experiments concentrated on the reaction of benzyl bromide at room temperature and one atmosphere carbon monoxide. We chose sodium hydroxide as the base, methanol as the solvent, and looked at the product distribution. We were interested in the selectivity to ester and the reactivity of this system. The results are given in Table III. 

Oxidation of hydroxamic esters in an alcoholic solvent may prove to be useful in certain cases. Phenyliodine(III)bis(trill uoroacetate) (PIFA) oxidation of the proline derivative (185) in trifluoroethanol afforded a 26% yield of the A-methoxy-Af-trifluoroethoxy derivative (187), presumably via an intermediate Af-methoxy-A-acylnitrenium ion (186) (equation 23). ... 

Ester, alcohol, and most ketone solvents also decompose. 

Organic solvent Time (h) Conv. (%) Optical purity (% ) Ester Alcohol E value... 

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